Polarized electromagnetic relay

ABSTRACT

A polarized electromagnetic relay of the conductor plate type in which a single permanent magnet is disposed between body portions of an E-shaped core yoke and a U-shaped yoke. A U-shaped armature is resiliently supported coaxially of its legs from the body portion of the E-shaped core yoke for swinging movement between the yokes. The center leg of the E-shaped core yoke is longer than the outer legs and in response to a reversal of direction of flux in the armature, the armature moves between first and second stable positions in which it bears against the legs of the Ushaped yoke and the free end of the center, and the free ends of the outer legs, respectively, of the E-shaped core yoke.

[73] Assignee: Hartmann &.

United States Patent [191 Kuipers et al.

541 POLARIZED ELECTROMAGNETIC I RELAY [75] Inventors: Egbert Kuipers, Heiligenhaus; Paul Giinnewig, Essen; Horst Menz, Lintorf, all of Germany Braun Aktiengesellschaft, Frankfurt am Main, Germany [22] Filed: Nov. 3, 1971 211 Appl. No.: 195,435

[30] Foreign Application Priority Data Nov. 3, 1970 Germany ..P 20 54 051.6 Feb. 12,1971 Germany ..P 21 06 764.1

[52-] US. Cl ..335/230, 335/234 [51] Int. Cl.. ..H0lf 7/08 [58] Field of Search ..335/229, 230, 276, 234

I [561 References Cited UNITED STATES PATENTS 3,195,023 Ueberschuss et al ..335/230 [111 3,710,290 51 Jan. 9, 1973 5/1967 Adams ..335/230 3,518,592 6/1970 Bosch 3,533,033 10/1970' Allen 3,621,419 11/1971 Adams .L1..335/23() Primary Era'minerGeorge Harris Attorney-George H. Spencer et a1.

[57] ABSTRACT A polarized electromagnetic relay of the conductor plate type in which a single permanent magnet is disposed between body portions of an E-shaped core yoke and a U-shaped yoke. A U-shaped armature is resiliently supported coaxially of its legs from the body portion of the E-shaped core yoke for swinging movement between the yokes. The center leg of the E- shaped core yoke is longer than the outer legs and in response to a reversal of direction of flux in the armature, the armature moves between first and second stable positions in which it bears against the legs of the U-shaped yoke and the free end of the center, and the free ends of the outer legs, respectively, of the E- shaped core yoke.

14 Claims, 6 Drawing Figures PATENFEUJAN a ma SHEET 1 [IF 2 FIG. 3

FIG. 2

PATENTED JAN 9 i875 SHEET 2 BF 2 FIG. 5

POLARIZED ELECTROMAGNETIC RELAY BACKGROUND OF THE INVENTION The present invention relates to a polarized electromagnetic relay and particularly to a polarized conductor plate relay.

Polarized electromagnetic relays in which permanent magnets are incorporated in the magnetic circuits to produce two stable positions for the armature are known in the art. Thus, a polarized conductor plate relay which is part of the state of the art generally comprises an E-shaped core yoke, a U-shaped armature, a coil, a set of contact springs disposed below the magnetic circuit and two permanent magnets which are identified as the main magnet and the auxiliary magnet. The main magnet, which is block-shaped, is glued to the end of the center leg of the E-shaped core yoke and is magnetized in a direction perpendicular to the yoke plane. The auxiliary magnet is connected with the coil body above the armature in such a manner that it holds the armature in the flipped-up position. The two magnets a re thus positioned to lie above and below the U- shaped armature. In this construction, the magnetic flux emanating from the coil is conducted over the main magnet. Consequently, the main magnet represents an increased magnetic resistance for this flux in the magnetic circuit. Another drawback of this type of construction is that at least the main magnet must be fastened by some sort of gluing process. Moreover, the size of the two magnets is rather limited so that no strong holding forces can be produced.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to arrange the magnetic circuit for polarized relays in such a manner that a single permanent magnet can be used.

It is another object of the invention to provide means whereby this magnet can be easily and inexpensively mounted on the relay so as to furnish strong holding forces for the armature.

A still further object of the invention is to accommodate the permanent magnet at a point in the magnetic circuit where there is a relatively large amount of space so that the outer dimensions of the relay as a whole do not have to be increased.

It is yet another object of the present invention to substantially reduce the excitation energy required to operate such a polarized relay and at the same time even more simplify the structural configuration of the relay.

One embodiment of the present invention involves the use of a block-shaped permanent magnet which is disposed between the transverse bar of the E-shaped core yoke and a U-shaped yoke. The outer legs of the -E-shaped core yoke are shorter than the center leg and the edges at the ends of these outer legs serve as knifeedge bearing points for a U-shaped annature resiliently held between the E-shaped core yoke and the U-shaped yoke. In a first stable position, the U-shaped armature is held between the U-shaped yoke and the center leg of the E-shaped core yoke and in a second stable position, with a reversal of the direction of flux in the armature, between the U-shaped yoke and the outer legs of the E-shape'd core yoke.

Another embodiment of the present invention involves the use of resilient means which are fastened to the transverse bar of the E-shaped core yoke and to the underside of the armature at the level of its imaginary axis of rotation.

According to this further embodiment, armature and core yokes are planar in the area of their contact surfaces and the resilient means provide a positive air gap in the area of these contact surfaces.

In this embodiment, the resilient means are very long and narrow springs which engage the armature at the imaginary axis of rotation, the spring moment acting on the armature remains low so that less excitation energy for the relay is required. Since the contact surfaces between the outer legs of the E-shaped core yoke and the armature are kept planar, additional process steps relay is not increased. Thus, substantially the same parts can be used for both polarized and nonpolarized embodiments of the relay.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an expanded perspective view of one embodiment of the magnetic circuit of a polarized relay according to the invention.

FIG. 2 is a side elevational view showing the armature position of the relay of FIG. I in a first stable switching position.

FIG. 3 is a side elevational view showing the armature position of the relay in a second stable switching position.

FIG. 4 is an expanded view of another embodiment of the relay.

FIG. 5 is a side elevational view showing the magnetic circuits of the relay of FIG. 4 and the armature position is illustrated schematically when in a first stable switching position. 7

FIG. 6 is a side elevational view similar to FIG. 5 but shows the armature in a second stable switching position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS knife-edge bearings for the armature, generally shown at 3, in a manner to be described later.

The armature 3 is U-shaped and the legs 3a and 3b of the armature are connected with springs 4 and having flanges 4' and 5', respectively. A block-shaped permanent magnet 6 has a slit 6a at its lower rear edge into which the flanges 4' and 5' of springs 4 and 5 can beinserted. Above the permanent magnet 6 a U-shaped yoke 7 is shown whose legs 70 and 7b are approximately the same length as the center leg 1a of the E-shaped core yoke 1.

As seen in FIG. 1, core yoke 1, permanent magnet 6 and U-shaped yoke 7 each have openings therethrough which can be aligned in the manner indicated by the dash-dot lines so'that these components of the relay can be secured together by suitable means such as fastening screws, not shown. When assembled, these 7 components are positioned as seen in FIGS. 2 and 3 with permanent magnet 6 bearing on end leg 1d of core yoke 1 and with flanges 4' and 5' of springs 4 and 5 confined in slit 6a. U-shaped yoke 7 rests on permanent magnet 6 with legs 7a and 7b aligned with legs 3a and 3b as well as with legs 1b and 1c.

In addition to the above-described components, a contact actuation slide, generally shown at 8, has upstanding lugs 8a and 8b which are designed to be guidingly received on center leg la of core yoke 1, as best seen in FIGS. 2 and 3. The lower edge 80 of slide 8 is adapted to ride on the switching contact 9, schematically shown in FIGS. 2 and 3, forming part of a contact spring element, not shown, which can be connected to the relay by means of the above-mentioned fastening screws in a desired manner. Leg 3c of armature 3 rests on the top edges of lugs 80 and 8b so that movement of the armature 3, in a manner to be described below, is translated into movement of contact actuation slide 8 and switching contact 9 in a contact set. In a known manner, slide 8 is movable within a molded-on guide, not shown, associated with coil body 2.

FIG. 2 shows the magnetic circuit of a relay in the first stable position in which leg 3a of the U-shaped armature 3 rests on slanted end 1a, the centerleg 1a on the core yoke l and legs 3a and 3b bear upward on legs 7a and 7b of the U-shaped yoke 7. In the illustrated armature position, spring 4 and spring 5, not seen, are curved upwardly. The illustrated'characters N and S show that the magnet 6 is magnetized in a direction perpendicular to the planes of the yokes. The path of the flux through the parts which can be formed from suitable material, such as iron, is shown with dashed lines.

FIG. 3 shows the second stable position of the armature 3. In this position, leg 3c of armature 3 contacts the ends of the legs 7a and 7b of the U-shaped yoke 7. Simultaneously, legs 3a and 3b, with the underlying portions of springs 4 and 5, respectively, bear against knife-edge bearings 1d and 1e on legs 1b and 1c of the E-shaped core yoke 1. Spring 4 and spring 5, not seen, inthis case lie flat on legs lb and 10, respectively. The path of the flux in the magnetic circuit is again shown with dashed lines.

A comparison of FIGS. 2 and 3 reveals that the direction of flux in the legs of the U-shaped armature 3 is reversed when the relay is switched by current pulses in the excitation coil 2. Thus the electromagnetic flux points so that the upper right edges of the armature can 7 flowing in theone or the other direction'is superirn- I posed on the flux produced by permanent magnet 6 in such a manner that the armature changes its stable position. The individual phases of these movements are described below.

If, in FIG. 3, the left end of armature 3 is moved downwardly, the armature-rolls from the edges 1d and 1e which act as knife-edge bearings. The right upper edges 3a and 3b of armature 3 thus come close to the arms 7a and 7b on yoke 7 to such an extent that these edges are pulled up to the yoke 7 by the forces of the permanent magnet. Thus, the position shown in FIG. 2 has been reached. The magnetic forces occurring here are strong enough to overcome the spring forces of the switching contact 9. During switching from the position shown in FIG. 2 to a first stable position, shown in FIG. 3, the armature 3 is additionally accelerated by the forces of the switching contact 9.

It can be seen that, as the armature 3 is held in the position shown in FIG. 2, spring 4 is deformed relative- Iy strongly as is spring 5 which cannot be seen. For this reason, very slim springs of a non-ferromagnetic material are used so as to avoid the creation of an undesired magnetic shunt. If desired, the springs may,.of course, also have downwardly bent flanges 4' and 5' to be fastened in slits, not shown, in legs lb and 1c. 2

It would also be conceivable to clamp the springs 4 and 5 flat underneath the permanent magnet 6, but this would result in an additional air gap. The armature springs can also be entirely eliminated if the armature is guided, by the appropriate shape of the relay housing (not shown), so that the armature can perform the switching movements without slipping out of its intended position. g

In a further modification of the structure according to the present invention as disclosed in FIGS. 1-3, the bending upward of the edges 1d and he on legs lb and 1c could be omitted if the armature 3 is appropriately deformed at its bearing point with these legs as, for example, with a downward bulge. In this case, legs 1b and 10 can have the same length as leg 1a without this interfering with the principle of the invention. However, it may be vadvisable to use the illustrated embodiment because of the saving in weight in the relay. It is important, however, in any case, that the legs 3 a and 3b of the U-shaped armature 3 be extended beyond the bearing come sufficiently close to legs 7a and 7b on yoke 7.

The polarized relay constructed according to the principle of the present invention develops extraordinarily strong holding forces so that multiple contact sets with strong contact forces can be used.

The height of the magnet 6 and yoke 7 can be so dimensioned that yoke 7 will not extendv above the upper limit of the body of the excitation coil 2 and consequently no additional installation space is required.

The illustrated polarized relay differs from a nonpolarized relay only in that is has a different core yoke 1, different armature springs 4 and 5 and an additional magnet 6 and an additional yoke 7. All other parts, as for example the coil body and the contact spring body, can be used without modification as provided in known constructions.

The springs 4, 5 which consist of nonferromagnetic material are fastened to the undersides .of the legs 3a and 3b of armature 3 so as to intentionally provide air gaps between armature 3 and the bearing edges 1d and 1e.

In a further modification, the permanent magnet 6 could have a structural height less than the distance between the U-shaped yoke 7 and the E-shaped core yoke 1. This could be accomplished by an intermediate layer of iron sheets. The result would be a change in the distribution of flux due to the change of the air gap at the location of the permanent magnet.

Another embodiment of the invention is shown in FIG. 4 where a contact supporting body llreceives a coil body 12. The E-shaped core yoke, generally indicated at 13, is placed with its .center leg 130 through the opening in coil body 12. The outer legs 13b, 13c of the core yoke 13 are shorter than leg 13a and are provided with planar contact surfaces for the U-shaped armature, generally indicated at 14.

Legs 14a and 14b of armature 14 are connected with armature holding springs 15, 16, which are relatively long and narrow. The holding springs are widened at their right-hand end, as seen in FIG. 4, and are provided with recesses 15' and 16' which are adapted to the corresponding fastening protrusions 13 on the transverse portion 13d of the Eshaped core yoke 13.

Springs 15 and 16 are fastened by welding or riveting to the underside of armature 14 at the level of the imaginary armature axis of rotation A-B of the armature in the relay. With this type of fastening, the springs are portion 13d of the E-shaped core yoke l3'and the U shaped yoke 18 by means of screws 19, 20, which extend into contact support body 11. The magnet is provided at its sides with semicylindrical recesses 17a and 17b which effect an automatic alignment of the magnet between screws 19, 20. The magnet is magnetized in the direction of its shortest dimension.

For the defined fastening of the U-shaped yoke 18 with respect to yoke 13, two plastic blocks 21 and 22 are provided which have the same thickness as magnet 17. These plastic blocks are provided with recesses, not shown, at their underside into which the fastening protrusions 13' of the E-shaped core yoke .13 engage. In their left-hand portion, as viewed in FIG. 4, the plastic blocks 21 and 22 are provided with tunnelshaped recesses, not shown, which permit free but guided movement of springs 15 and 16 within these blocks during the switching process to be explained below.

A plastic actuation slide 23 is displaceably mounted in a recess, not shown, of the left-hand flange 12' of coil body 12. In a manner similar to that illustrated in conjunction with the first embodiment of the invention, the slide is associated withcontact springs, not shown.

To facilitate mounting, springs 15, 16 can be connected together by an auxiliary bar 24, which is appropriately scored for subsequent breaking off. An auxiliary bar 25 connects plastic blocks 21 and 22 before their installation and is also scored. The auxiliary bars 24 and 25 are either manually broken off when the relay is completely assembled or they are cut off by a machine.

As seen in FIG. 4, the center leg 13a of the E-shaped core yoke 13 has a reduced cross section at its left-hand end andis slanted at its upper side as indicated at 13a.

This reduction in cross section effects, in conjunction with the corresponding reduction in cross section of leg 14c at the armature 14, a so-called isthmus effect which substantially improves the switching behavior of the relay. The slanted upper surface has the effect that the leg 14c of armature 14 is in full contact with the center leg 13a of the core yoke 13 at 13a in the one switching position as will be explained later.

FIG. 5 is a schematic illustration, in a side view, of the magnetic circuit of the relay with the plastic blocks 21 and 22 not shown so as to provide a clearer view of the armature movement. The permanent magnet 17 is disposed above the E-shaped core yoke 13, the magnet being magnetized according to the pole indications N and S. Above the magnet lies the U-shaped yoke 18. The coil 12 which is disposed on the center leg 13a of the core yoke, is only indicated. The U-shaped armamm 14 takes up a first stable position which corresponds to the rest position of the relay. In this rest position the contact springs are not deflected and the rest contacts are therefore closed in a manner similar to that shown in FIG. 3.

It can be seen from FIG. 5 that the permanent magnetic flux from the north pole of the magnet 17 continues over the U-shaped yoke 18, armature 14 and the shorter outer legs 13b and of the E-shaped core yoke 13. If now coil 12 is so excited that a strong north pole is produced at the end of the core yoke leg 13a, the transverse portion of the U-shaped armature 14 is attracted by this north pole and the armature flips into the second stable position which is shown in FIG. 6. At this switching process, the direction of flux in the legs 14a and 14b of the armature 14 is reversed. The contact springs are switched to the operating position in a manner as illustrated in FIG. 2. When the switching pulse has died out, the permanent magnetic flux passes from the north pole of the magnet 17 over the legs of the U-shaped yoke 18, armature l4 and the center leg 13a of the E-shaped core yoke 13 to the south pole of the magnet.

If now the coil is excited in the opposite direction, the coil field is superimposed on that of the permanent magnet is such a way that the armature 14 is pushed away from the second stable position and returns to its first stable position.

The number of ampere windings of the coil 12 for the available operating air gaps so that it changes from the one stable position to the other.

It will be understood that the above description of the prevent invention is susceptible to various modifications, changes and adaptations and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. In a polarized electromagnetic relay of the conductor plate type having an E-shaped core yoke with a transverse bar connecting a center leg and a pair of outer legs, a U-shaped armature with a transverse leg connecting a pair of legs and movably mounted on the core yoke for selective contact with the ends of the core yoke, the improvement which coniprises rincom -mane nt' fhagnet has a lesser structural height than the bination:

a. a block-shaped permanent magnet disposed on the.

transverse bar of the E-shaped core yoke; b. a U shaped yoke with a transverse leg interconnecting'a pair of legs, said transverse leg of the yoke being disposed 'on top of said permanent magnet and with the pair of legs in alignment with d. the center leg of the E-shaped core yoke having a s free end that extends beyond the free ends of the pair of outer legs, the free ends of the pair of outer legs providing a bearing point for the associated legs of the U-shaped armature, whereby the armature is held in a first stable position between the U- shaped yoke and the free end of the center leg of theE-shaped core yoke and then in a second stable position between the U-shaped yoke and free ends of the pair of outer legs of the E-shaped core yoke when there is a reversal of flux in the armature.

2. A relay as defined in claim 1 wherein the free ends of the pair of outer legs of the E-shaped core yoke are angled upwardly.

3. A relay as'defined in claim 1 wherein said means are relatively narrow holding springs.

4. A relay as defined in claim 3 wherein the holding springs are of nonferro'magnetic material and are fastened to the underside of the free ends of the armature legs to provide an air gap between the free end of said pair of legs on the armature and the free ends of the associated outer legs on said E-shaped core yoke when the armature is in the second stable position.

5. A relay as defined in claim 1 wherein the U-shaped armature is supported only at the pair of legs.

6. A relay as defined in claim 1 wherein said perdistance between said U-shaped yoke and the E-shaped core yoke. V

7. A relay as defined in claim 1 wherein said means are elongate holding springs which are fastened to the transverse bar of the E-shaped core yoke and to the underside of the pair of legs of the armature at the imaginary axis of rotation of the. armature with respect to the core yoke.

8. A relay as defined in claim 7 wherein the' height of a the permanent magnet is approximately oneandone half to twice that of the thickness of the U-shaped armature.

9. A relay as defined in claim 7 wherein the armature and the core yoke are planar in the area of their contact surfaces and said springs form a positive air gap at these contact surfaces.

10. A relay as defined in claim 7 wherein said blockshaped permanent magnet is disposed between two shaped core oke is provided with protrusions at the point where e springs are fastene and where n the springs and said plastic blocks are provided with cor responding recesses, l

13- A relay as defined in claim 1 1 wherein the springs and said plastic blocks are provided, in pairs, with disposable transverse bars which are scored for breaking off from said springs and said blocks. 7

14. A relay as defined in claim 11 wherein said plastic blocks are provided with recesses at their undersides which encompass said springs and permit unimpeded deformation of said springs during switching from one stable position to another. 

1. In a polarized electromagnetic relay of the conductor plate type having an E-shaped core yoke with a transverse bar connecting a center leg and a pair of outer legs, a U-shaped armature with a transverse leg connecting a pair of legs and movably mounted on the core yoke for selective contact with the ends of the core yoke, the improvement which comprises, in combination: a. a block-shaped permanent magnet disposed on the transverse bar of the E-shaped core yoke; b. a U-shaped yoke with a transverse leg interconnecting a pair of legs, said transverse leg of the yoke being disposed on top of said permanent magnet and with the pair of legs in alignment with the pair of outer legs of the E-shaped core yoke; c. means extending between the armature and the E-shaped core yoke to mount the armature for movement between the legs of the E-shaped core yoke and said U-shaped yoke; and d. the center leg of the E-shaped core yoke having a free end that extends beyond the free ends of the pair of outer legs, the free ends of the pair of outer legs providing a bearing point for the associated legs of the U-shaped armature, whereby the armature is held in a first stable position between the Ushaped yoke and the free end of the center leg of the E-shaped core yoke and then in a second stable position between the Ushaped yoke and free ends of the pair of outer legs of the Eshaped core yoke when there is a reversal of flux in the armature.
 2. A relay as defined in claim 1 wherein the free ends of the pair of outer legs of the E-shaped core yoke are angled upwardly.
 3. A relay as defined in claim 1 wherein said means are relatively narrow holding springs.
 4. A relay as defined in claim 3 wherein the holding springs are of nonferromagnetic material and are fastened to the underside of the free ends of the armature legs to provide an air gap between the free end of said pair of legs on the armature and the free ends of the associated outer legs on said E-shaped core yoke when the armature is in the second stable position.
 5. A relay as defined in claim 1 wherein the U-shaped armature is supported only at the pair of legs.
 6. A relay as defined in claim 1 wherein said permanent magnet has a lesser structural height than the distance between said U-shaped yoke and the E-shaped core yoke.
 7. A relay as defined in claim 1 wherein said means are elongate holding springs which are fastened to the transverse bar of the E-shaped core yoke and to the underside of the pair of legs of the armature at the imaginary axis of rotation of the armature with respect to the core yoke.
 8. A relay as defined in claim 7 wherein the height of the permanent magnet is approximately one and one half to twice that of the thickness of the U-shaped armature.
 9. A relay as defined in claim 7 wherein the armature and the core yoke are planar in the area of their contact surfaces and said springs form a positive air gap at these contact surfaces.
 10. A relay as defined in claim 7 wherein said block-shaped permanent magnet is disposed between two fastening screws.
 11. A relay as defined in claim 7 wherein plastic blocks of the same height of said permanent magnet are disposed between the outer legs of the E-shaped core yoke and the pair of legs of the U-shaped yoke.
 12. A relay as defined in claim 11 wherein the E-shaped core yoke is provided with protrusions at the point where the springs are fastened and wherein the springs and said plastic blocks are provided with corresponding recesses.
 13. A relay as defined in claim 11 wherein the springs and said plastic blocks are provided, in pairs, with disposable transverse bars which are scored for breaking off from said springs and said blocks.
 14. A relay as defined in claim 11 wherein said plastic blocks are provided with recesses at their undersides which encompass said springs and permit unimpeded deformation of said springs during switching from one stable position to another. 